public double FindSolution(Equation eq, double eps)
{
Console.WriteLine("\nNewton's Modified Method:\n");
Console.WriteLine($"Eps: {eps}");
Console.WriteLine($"Start: {eq.start}\nEnd: {eq.end}\n");
double x = (eq.start + eq.end) / 2;
double fvalue = eq.function(x);
Console.WriteLine("Initial approximation: " + String.Format("{0:f8}", x) +
" Function value: " + String.Format("{0:f8}", fvalue));
int i = 1;
while (Math.Abs(fvalue) - eps > 0)
{
// fvalue == eq.function(x) - це зроблено для уникання багатьох перераховувань функції
x -= (fvalue / eq.derivative(x));
fvalue = eq.function(x);
Console.WriteLine($"Iteration {i}: " + String.Format("{0:f8}", x) +
" Function value: " + String.Format("{0:f8}", fvalue));
i++;
}
Console.WriteLine("Result: " + String.Format("{0:f8}", x) +
" Function value: " + String.Format("{0:f8}", fvalue));
return(x);
}
public double FindSolution(Equation eq, double eps)
{
Console.WriteLine("\nSecant Method\n");
Console.WriteLine($"Eps: {eps}");
Console.WriteLine($"Start: {eq.start}\nEnd: {eq.end}\n");
double x = (eq.start + eq.end) / 2;
double fvalue = eq.function(x);
Console.WriteLine("Initial approximation: x0 = " + String.Format("{0:f7}", x) +
" Function value: " + String.Format("{0:f7}", fvalue));
double x_next = x - (fvalue / eq.derivative(x));
fvalue = eq.function(x_next);
Console.WriteLine("Second approximation: x1 = " + String.Format("{0:f7}", x_next) +
" Function value: " + String.Format("{0:f7}", fvalue));
int i = 1;
while (Math.Abs(fvalue) - eps > 0)
{
double t = x_next;
// fvalue == eq.function(x_next) - це зроблено для уникання багатьох перераховувань функції
x_next -= ((x_next - x) * fvalue) / (fvalue - eq.function(x));
x = t;
fvalue = eq.function(x_next);
Console.WriteLine($"Iteration {i}: " + String.Format("{0:f7}", x_next) +
" Function value: " + String.Format("{0:f7}", fvalue));
i++;
}
Console.WriteLine("Result: " + String.Format("{0:f7}", x_next) +
" Function value: " + String.Format("{0:f7}", fvalue));
return(x_next);
}